Group 7: Halogens
Read our general notes on Risk Assessment
In experiment 6.1 of the Nuffield course, when you have obtained your iodine extract in hydrocarbon solution, why does the purple colour fade after a week?
Igloo replies
The iodine volatilises away from its solution in the hydrocarbon solvent, so its concentration in the solution steadily drops, and, as you’ve already noticed, its purple colour fades as a consequence. If you had corked the solution, this fading would not have occurred.
Risk assessment
Before attempting any practical work based on the advice and suggestions on this website, you must do the following. Identify any hazards, assess the risks from these hazards, and then decide appropriate control measures to reduce the risks. You must have these approved by those in authority in your school or college laboratory. Do not rely on what is said on this website.
For further guidance see our tutorial on Risk Assessment.
Rate this page or react
Share your views on this page, 1 ratings so far
, rated at 
updated: 19 January 2005
